One of the goals of medicine, including the surgical arts, is the recovery of health that has been lost, whether the loss occurred as a result of injury or disease. In the surgical arts, ever more effective treatment strategies for addressing cartilage defects are being sought. Such defects in joints (intra-articular) can result from a number of different causes, including trauma and diseases such as osteoarthritis. The hyalinic articular cartilage is a specialized connective tissue in the body with weight bearing and shock absorbing properties and functions. Injury to or loss of this specialized connective tissue in a joint leads to pain and impaired joint function.
Although the hyalinic articular cartilage does have some self-repairing capabilities, these are very limited. Therefore, the orthopedic surgical arts field has been motivated to develop therapies which replace or promote regeneration of damaged joint cartilage. This is in response to the large number of joint injuries that occur yearly, and the increasing number of the elderly with joint problems. Typically, these therapies are merely surgical methods which debride and mechanically repair the injury, with or without the addition to the injury site of an active composition to promote healing or to prevent inflammation/infection.
More recently, the field has tried bio-engineering influenced therapies which added a structural composition to the injury, such as autologous tissue grafts, in order to promote appropriate healing. However, osteochondral injuries, which are a combination lesion of bone and cartilage, represent therapeutic challenges, and fully satisfactory therapeutic compositions and treatment methods are still lacking in many cases. For example, certain surgical procedures for osteochondritis dissecans using autologous chondrocyte transplantation require extensive periods for the cell cultivation and growth aspect and multiple surgeries. Additionally, these therapies often result in the propagation of a fibrocartilaginous replacement tissue, which is a poor substitute for hyaline articular cartilage. See J. Kramer et al., Cell. Mol. Life Sci., 63, 616-626 (2006).
Therefore, it would be beneficial in the field to have alternative treatment for osteochondral injuries that do not require cell culture, and do not result in propagation of a fibrocartilaginous replacement tissue at the injury site. It would be even more advantageous if the resultant replacement tissue was appreciably representative of natural hyalinelike articular cartilage.